The supermassive black hole lies at the dust- and gas-filled heart
of a galaxy called NGC 1365, and it is spinning almost as fast as
Einstein's theory of gravity will allow.

What is a Black Hole?

A black hole is an area in space where gravity is so strong
that even light cannot escape from it and
appears black. Nothing can escape from a black hole.

It is not really a hole and it is
not empty. It is filled with a lot of material squeezed into an
extremely small space. As a result this is what gives a black hole
its super strong gravity.

How are black holes made?

Scientists think that black holes are created in places where
matter gets extremely dense. This can happen in the centers of
large galaxies or when a giant star collapses and shrinks during
the final phases of its life.

A Black Hole Concept Drawing by
NASA.

Types of Black Holes

There are three types of black
holes:

1. Stellar Black Holes: Form when a
massive star collapses.

These are created when massive
stars reach the ends of their lives and run out of fuel, exploding
in powerful blasts called supernovas. The left-over material from
the explosion collapses into itself and becomes a black hole. A
typical stellar-mass black hole contains the mass of about 10
suns.

2.
Supermassive Black Holes: have a mass equivalent to
billions of suns. They are likely to exist in the centers of most
galaxies, including our own Milky Way Galaxy.

3.
Miniature Black Holes: No one has ever discovered a
miniature black hole. The mass would be much smaller than that of
our Sun.

Is there a black hole at the
center of our Milky Way Galaxy?

There is a very large black hole at the center of our galaxy.
It has a mass of about three million suns and is located 24,000 light-years
from Earth.

Size

Black Hole is a region of space
having a gravitational field so intense that no matter or
radiation can escape.

Locations

It is now believed that at the
center of each galaxy there is a super-massive black hole. Many
have already been detected.

Event Horizon

Event Horizon is the critical
distance at which nothing can escape. Even light cannot travel
back out of a black hole after crossing the Event Horizon.

History

John Michell of England and
Pierre-Simon Laplace of France independently suggested the
existence of an 'invisible star' using Newton’s Laws in the late
1790s.

In 1915, Einstein's theory of
general relativity predicted the existence of black holes.

In 1967 John Wheeler, an American
theoretical physicist, applied the term 'black hole' to these
collapsed objects.

Discovery

Cygnus X-1 was the first object
to be considered a black hole. No black hole has actually been
imaged in a telescope.